Alternating-current telegraph system



1927. May 3l W..M. BRUCE, JR

ALTERNATING CURRENT TELEGRAPH SYSTEM e sheds-sheet 1 Filed April 28. 1924 attorno/jo May 31, 19275 1,630,827 W. M. BRUCE, JR

ALTERNATING CURRENT TELEGRAPH SYSTEM Filed April 28. 1924 6 Sheets-Sheet 2 May 31 1927.

1,630,827 w. M. BRUCE, JR

ALTERNATING CURRENT TELEGRAPH SYSTEM 6 Sheets-Sheet 5 Filed April 2B. 1924 ay '3 w. M. BRUCE, JR

ALTERNATING CURRENT TELEGRAPH SYSTEM 6 Sheets-Sheet 4 Filed April 2a. 1924 @Hotuctd 1,630,827 May 31 1927- w, M. BRUCE.VJR

ALTERNATING CURRENT TELEGRAPH SYSTEM l Filed April '2a. 1924 e sheets-sheet 5` May 3l 1927.

W. M. BRUCE, JR

ALTERNATING CURRENT TELEGRAPH SYSTEM Filed April 2s, 1924 e sheets-'sheet 6 atented ay 3i, 12'?,

WILLIAM M. BRUCE, JR., OF SPRINGFIELD, GEIQ.

ALTERNATING-VCUBRENT TELEGRAPH SYSTEM.

A Application led April 28, 1924. Serial No. 709,349.

My invention relates to a system and apparatus of telegraphy. adapted for telegraphing over submarine cables or lines of high capacity but may be 5 used with advantage in anyl kind of telegraph lines.

The object of my invention is to provide means for increasing the speed and decreasing the errors in telegraphic transmission and I accomplish this object primarily in methods and apparatus by means of which the transmission is accomplished by alternating current.

The invention consists in various methods and apparatus and circuits hereinafter described and set forth in the claims.

In carrying out my invention I employ the ordinary continental Morse code of telegraphing but I transmit and receive the code elements of dots and dashes in such a way that each successive element is transmitted by a different polarity of current Whether it be a dot or dash. If there are a series of dots one will be sent with a positive impulse, the next with a negative impulse and the same is true of the dashes or whether a dot follows a dash, each impulse representing a code element being a reversal from the precedingv one, hence the transmission is by alternating current. v

I further preferably make provisions for sending these reversals continuously on the line whether code elements are being transmitted or not and I secure the transmission of the code elements by increasing the current at each half cycle at which a code element is transmitted, the increase in the impulse being greater for one code element than another so thatthe characters are of the same duration or fundament-a1 frequency but ofdii'l'erent amplitudes and AWhen recorded will be represented by longer or shorter marks above or below zero.

I further provide means for rectifying the A signals when they are received and recorded so that the signals may be. recorded by long and short vertical characters that can be very easily read.

lVhile I preferably use means for sup- I0 plying alternating current to the transmission line at all times the system is 'applicable to one in which the current impulses are supplied only to the particular code ele- It is especially' ments, that is the dots or dashes, but in any case there will be an alternation of polarity, each succeeding'element representing a reversal from the preceding one. l

I further preferably provide that in introducing the alternating current to the transmission lines each current impulse or signal shall be supplied to the'line in graduated steps so that the resulting signal impulse is approximately of sine wave form.

The system is not' only ada ted to the direct transmission of cable co e from one station to another but also lends itself readily to automatic repeating from one line to another and also to amplification at receiving or repeating stations by the use of thermionic tube amplifiers which is a part of the present invention.

In the accompanying drawings:

Fig. 1 is a diagrammatic view showing circuits and arrangements of the apparatus for transmitting the signal and signal elements at a cable terminal.

-v Fig. 2 is a similar view of the receiving 4the ordinary automatic tape transmitting device of standard character.

Figs. 7, 8, 9 and 10 are detailed views hereafter referred to. v u

Like parts are represented byv similar letters of reference in the several views.

It may be stated at the outset that this improved system for transmitting and receiving cable signals may be used for the most part with the standard apparatus, for instance the transmission 'is accomplished by the standard automatic cable tape transmitter adapted to make the dot and dash contacts through the medium of contacting devices operated by a perforated tape. S0 also the received record may be received on the contacting devices in any standard cable tape transmitting device, the one A being .adapted tc make a contact for a dot and the one B for a dash. c and ci are relays that are operated when their circuits are closed at A or B. These relays would correspond to the ordinary transmitting relays in a cable circuit. The circuit for the relay c may be traced from A by wire 1 to magnet of relay c, wires 2 and 3 to battery 4 and thence by wires 5 and 6 to the contacting lever 7 at Contact A. The circuit for relay d can be traced from contact B by wire 8 to coil of relay ci, wires 9 and 3, battery 4,

. wires 5 and 10 to lever 11 of contact B.

It will be understood that these dot and /dash relays c and a?, if connected in the orainary way with the battery and cable, would represent the usual method of transmitting dots and dashes in the present cable systems by supplying circuit of one polarity for a `dot and of opposite polarity for .a dash.

In order, however, to provide for a semisinus or half cycle for each signal element either a dot or a dash I preferably employ a source of direct current such as the usual cable battery with a pole changing controlling device which will be associated with the cable transmitter in such a way as to move positively therewith and effect a change in the polarity of the battery at each step or center hole of the tape transmitter. This pole changing and controlling device preferably consists of rotating brushes which will be connected to o posite ends of the transmission line, one oi) these brushes being connected direct to-:the transmission lines such as a cable and the other to the opposite end through the usual earth connection and I arrange to have these brushes make a half revolution for each center hole or half cycle during which each polarity of battery will be connected directly to the cable and during the opposite half of the revolution the opposite polarity of the battery will be con-l nected directly to the cable so that for each revolution of the pole changer We will have one cycle of an alternating current.

This pole changing device in addition to the rotating brushes is preferably provided with a series of contacts or segments which are connected together successively by resistance and the positive and negative pole ofthe battery are connected to opposite segments which are arranged ninety degrees from the normal or zero segments which are connected to earth.

In Fig. 1 this pole changing controlling device is shown at E and the main battery at ai. The rotating brushes are shown at W and W and normally rest on the zero contacts or'segments S and S. The brush or wiper W is connected as indicated by wire 12 direct to the apex of the cable in the usual way while brush W will be Vconnected to the opposite end of the cable through earth as indicated at G2, thesegments S and S being earthed or. grounded at G and Gr.`

The positive side `.offthe battery w is connected to segment SP by wire 1.3 and the K negative side of the battery is connected to segment SN through lWire la, resistance 15 and 16 and wire 17;

pole changing controlling device forms a Wheatstone bridge connected to opposite sides of the battery, the four arms of which are equal and no current will flow from the wiper W towiper W. l

These wipers W and W being arranged on the same shaft and geared directly to the cable transmitting device` will travel in the direction of the arrows, the wiper IV passing and contacting successively with those segments which may be called positive segments from S to S', while the wiper W will contact successively with what may be called negative segments from S to S. As soon as the wipers leave the earthed segments S and S the balance of the Wheatstone bridge will be disturbed and current will'begin to flow from the positive side of the battery through the cable to earth and through W to the negative side of the battery and thus current flow to the cable will gradually increase as these wipers pass over the res-pective segments until they have travelled a distance of ninety degrees and wiper W rests upon the segment SP and wiper W rest upon segment SN, at which time we will have a direct connection from the positive to the negative side of the battery through the cable or other transmission line and the full potential of the battery will be supplied to the cable except for the resistances.v 15 and 16 which will cut down the battery travelled one hundred eighty degrees or one half revolution when the wiper W will rest upon segments S and the wiper W will rest upon segment S at which time the so In this position as indicated in Fig. 1 the Vheatstone bridge balance will be restored, f

and current will cease to flow from battery to the cable and the cable will be directly earthed at G', thus discharging the same.

This completes one half cycle which by reason of the decreasing and then the gradual increasing of the resistances between the respective segments will charge the ing a sine wave form of impulse.

. 1 to relay c thence 'through wires 2 and to battery m2 andv wire 23 to the armai W and W.

-approximate sine wave form.

As the wiper continues to revolve W will now begin to transverse the positive segments and wiper 'W will transverse the negative segments and the operation will be .repeated with negative battery supplied to the cable and the positive battery connected to earth and after a complete revolutionand the parts have returned to normal posltion as indicated in Fig. 1, a completel cycle will have been secured with a reversal of polarity at each half cycle. thus producing one cycle of an alternating current of an As long as the transmitting device with the wipersl continue to operate alternating current will be supplied to the cable one half cycle for each center hole in the tape, but the resistances 15 and 16 are such that the current thus supplied to the cable will be controlled by the resistances 15 and 16. For signalling, means are provided to shunt the resistances 15 and 16 to produce the desired diference in amplitude between dots and dashes.

For instance, if a dot is to be transmitted 4the automatic transmitter will operate the dot contact or pecker pin closing the circuit for the relay c at contact A through the circuit heretofore described. This will energize the relay c and operate its armature c1.v Opposite the armature c1 are two contacts c2 and c3. The first of these contacts c2 is in a circuit as follows: from c2 through wire 18, contacts 19 and 20, wires 21 and ture c1. The contacts 19 and 20 are normally open and are held in this position by a cam on the same shaft with the Wipers At the first movement of this shaft from normal position the cam will release the contacts which will close auto-A matically. This locks the armature in its operated position during the entire move-v ment of the wipersover the segments as hereinbeforedescribed, that is during a onehalf revolution or half cycle at which time the cam will open contacts 19 and 20 and:

- 25, (thus shunting the resistance 15) and thence through the resistance 16, wire 17 to ne ative battery 'at SN. During this one half revolution of the wipers, thereforethe current How of the one-half cycle will be increased by cutting out the resistance 15,

thus producing the dot element or amplitude. y

If the dash contact is closed at B the re'- lay d `Vwill be operated over the circuit hereinbeforedescribed through wire 8, relay fd, wires 9'and 3. battery wires 5 and 10 to contact B. The armature d1. of this relay 4is also provided with two contacts d2 and d, one of which is connected4 through Wire 27, contacts 28 and 29, vwire30 .to wires8 and 9 and battery :v2 and wire 23 to the armature d?. The contacts 28 and 29 are operated in 'a similar way by a cam which permits the v contacts to 'close at the first' movement of the shaft after the dash consol tact has been closed and holds the relay d energized during the' one-half revolution. The contact da is connected by wire 31 to wire 17A at the point 32 so that negative battery would' be connected vfrom point 26V through wire 23, armature d1, contact d3, Wire 31 to Wire 17 at 32, thus shunting the resistances 15 and 1.6v and allowing the full potential of the battery to be lsupplied* to the pole changing and controlling device.

By this arrangement when eithera 'dot or a dash Contact is closed thehalf cycle.

whether negative or positive at which it oc- V curs will have its potential augmented byl a small or a larger amount, dependingl upon whether-.it is a dot or a Adash and the signal elements introduced in the cablewill appear for ease in reading and asa part of myv s stem I have provided a new .and novel vmeans for receivingthese signals and this mayv be described as follows, having particular reference to Fig.v 2'..-

In this View R is areceiver preferably of the usual galvanometer or movable coil type which Will be connected ltov the cable .in the.

usual way. It is provided with a movable tongue t which is adapted to contact with different segments of a' revolving drum somewhat lsimilar to that used in the well known Brown drum relay; The tongue t,

normally yrests on the zero `or no mans land on each side of which there are two contacttongue due to the valternating current passing continually into the cable will not move it suliicientl'y .to engagev theA doty contacts.

`land is of such size that thejexcur'sion of the 215 be such 'as' shown in Fig. 2a.

' when this alternating @gaat or any half o 'tive or"negati\ 7e` g and ifsoconnected when' a currenti pulsev is augmented to a greater or less exten ,the

"l increase in the potential of the positiveor negative cycles will' causethe syphon re'- corder'to move in one direction or the other to a vgreaterfor less l'extentmaking a ,shorter mark fora dot and allonger markgpfora J2 dash." These longer and shorter mark ,how-

'ever-,would be on either side ofthe ro depending on whether it is apositiver negativecycle which "receives the modulated increase and the record. in that casewould l `AAI prefer, however, to use means for rectifying or changing the form of the signal so that the short and long marks" will always vbe in substantially vertical lines and this I 3" accomplish as follows: z

The dot anddas'hsegmentsf and -f of the rotating" contactare' preferably. connected to the grid elementsv of vacuum tube relays VT and VT While the platecircuit's of 5 these respective vacuum tubes are connected through va suitable battery v3 to relays R and R2. These vacuum tuberelays may be similar to that d escribed in my pending applica-v tion Ser. No. 630,294. 40 The relay R when. energizedcloses a circ uit throughl contact33, variable' resistance 34, Wire 35, recorder 36, wire 37, -battery w,

-wire y38 to contact 39.- If the tongue, theref fpre, should moveto eitheroneof 'the inner v'ordot contacting segments /f on the drum Athe relay R would be energized and would operate the recorder 36fwhich may be of the vusual syphon recorder or .direct Writer type. If the tongue t should moveto one of the would 'be' energized .and would close a circuit from contact 40, wires 41 and 35, recorder 36, wire 37, battery and Wire 42 tothe contact 40. :This would operate the recorder 36 but inasmuch as the'first menltioned circuit. contains resistance 34 the re corder would be moved to a less distance when the relay R is operated than when relay R2 is operated and the recorded signals 2,-which represents an exact photographic reproduction of received signals transmitted in the form showni'n Fig. 2.

ing from one cable. or conductor to another heretofore-described.'

would appear as shown at the'bottom of Fig. 1'

In Fig. 3 I have shown means for repeat! andthis 'consists largelyof'acouibination of the receiving cir'c'uit shown'iin- Fig. 2 and the transmittingcircuit shown in Fig. 1 with transmit-- anging and' this essential d lti'eren'ce.Vv The -t ter. is eliminated andthexpole cli)e controlling device is operated directly by a are operated fromntlie relays R and R2 Iso' suitablemotoniu'id `the transmitting relays c, and d arranged to `short circuit orj shunt the resistances l5 and 16 in th'e battery circuit that if positiveor vnegative cycles of slightly.

increased i potential are received it operates" relay R and it in turn operates relay c while if one of l a greater increased potential v-is received itV operates relay R2 which will in turn energize relay-d. The arrangementfor A ie relays a and d during the half holding-t revolution of `the wipers-@is .the -same as' In repeating with this systemv it'uis vessen-- tial thatthe transmitting-pole changer and controlling device be synchronized with that at the repeating station and I accomplish vthis byva .stop and-start rmachanism of any usual ty'pe .which will stop the'ro tation of the Wipers at each half revolution and cause them to start only when -a signal is being sent at which time `the stopinechanism will be released and the\wiper s wil1 start to rotate coincident 'with' the beginning of the signal.` This I accomplish. in

l a .very simple way 'as shown in Fig-g-3..

It is obvious that Whenever 'a ysignal is received Whether adot or a dashthe tongue t will contact with Athe inner set vof contacts f' on one side of the vzero and-Will energize lVhen a dash is to be recorded.A

relay R'. l both 'dot and dash relays R and R2 are .operated and the recorder 36 will get the full potential of .the 'battery If the tongue moves to one of the dot contacts fthe recorder Will'get lessthan the full potential' of the battery and lthe result Will be a long or short verticalline as indicated in Fig. 1.

I make use of this fact for operating the start and stop device of thepole changer at the repeating 'station by placing the 'magnet which controls -the' stopy and start device in circuit with the contacts of the dot receiving relay R. This magnet is shown in Fig. 3

at m and the circuit for it can' be traced from battery a4, wires 37 and 43, magnet' fm, Wire 44, circuit closer 45, Wire 46 to contact 33. The circuit closer 45 is nor-v mally closed butf will be operated by a cam on the same shaftwith -the 'Wipers similar to that theretofore described -for the transmitting device sothat the circuit will be opened at the first movement of the shaft 1. It will be seen .that whenever the relay R is operated by the tonguetL contacting with' either. one of the inner or dot sets of contacts f the magnet m will be energized1 and thus start the pole ychanging and controlling device to revolving. The

iso

^ tate so that the only time that the magnetl circuit closer 45 is normally closed and is opened as soon `as the wipers begin to rom can be energized will be when the wipers are on the segments S and S. When the lmagnet is deenergized by opening the circuit at 45, the stop device will be released and stop the rotation of the Wipers at the half revolution unless a signal or signal element should be received at that time when the operation would be repeated.

In Fig. 6 the general arrangement of the parts for transmitting alternating current and alternating current signals is shown. In this view la. represents the usual automatic transmittingdevice operated by the perforated tape k1 in the usual manner. This maybe driven from a motor tzby means of the directl connected shaft las. Surrounding the sha and supported in a suitable frame ha are the segments S, S, SP, SN, etc., with which `the brushes W and W', secured to the shaft yh3 and insulated f'rom each other, rotate. In order to secure the necessary connections to the rotary brushes solid contacting rings h5 and ha are provided and auxiliary brushes or wipers are arranged to contact with these respective rings and form electrical connection between the sam'e and thezfsegment wipers vV and l. One of these*rings is connected to the cable andthe other to earth as explained. The circuit closers for holding up the transmitting relays e and d are connected at `20 and 29 with the cams hf for operating the same. In Fig. 7 the same parts are shown somewhat in diagram and in the nature of an elevation view. In Fig. 8 there is shown an arrangement of the parts for repeating. vIn this case the automatic transmitter h is omitted; a suitable clutch ha is provided between the motor and the shaft ltswhioh Will permit the shaft and its connected parts to stop While the motor continues to revolve. At 71.9 is shown the stop device on the shaft which operates in connection with the stop'mecha nism and magnet m. h1 shows the cam which operates the circuit breaker 45. The cams 72,7 for closing the holding circuits for the relays o and d are alsov indicated and a detail view of this is shown in Fig. 9.

It will be understood that in the normal position of the repeating device the circuit breaker 45 is closed and the circuit closers 30 and 29 are open. T he stop device is in the position shown in Fig. 3 with the wipers onl the ground segments S and S. The first movement of the 'tongue on thereceiver R energizes the magnet m and permits the shaft h3 to revolve carrying the wipers W and W. The first movement of the shaft releases the circuit closers 2O and 29 and opens the circuit closer 45. This permits a one-half revolution of Ithe shaft R2 operated from the tongue t of the receiver- R are employed as before, and the first move-` ment of the tongue t onto a dot contact is used to operate the starting mechanism through the magnet m and permit the brushes or wipers to begin their movement. These -brushes with their stop mechanism are so connected that they rotate one-half revolution and stop. During this rotation the n' respective brushes contact with segments arrangedin pairs, diametrically opposite each other and preferably in twoy concentric rows. The wipers or brushes are supported on arms of different lengths so that one brush or wiper contacts with the outer segment of the pair and the other wiper contacts with the inner segment of the pair. The arrangement is such that if the relay R is operated at the time these wipers are on the respective contact segment an impulse of one polarity is sent into the printer and when therelay R2 is operated an impulse of opposite olarity is sent through the printer so that t e printer receives impulses of positive and negative character in response to the dot and dash n signals instead of impulses of greater or less potential. In this case. as described for the repeater, the operation of the relay R repportioned to the time it takes the relay tongue to `pass over the dot contact and reach the dash contact of the receiving revolving drum relay and during this time the dot relay R will have been deenergized by the tongue t passing ofi' of Contact If the tongue t should-move only to the dot contact f of the revolving drum. vthen the relay R would be operated and the dot signal received would be transmitted to the rotating distributor, the arrangement being such as before described that the operation of the relays would be timed to the movement of the distributor so that the closing of the contacts ofirelays R and Rzatakes place only when the distributors are on ,the respective circuit closing contacts.

The circuit vfor operating the start an stop device is the same as that shown. in Fig.

' 3. If the Vrelay R should be operated' closing the circuit at 33`thefcircuit would be" l ing from the printer to line 37 and to the other side of the battery x4. In a similar Way the Contact 40 of the relay R2 is connected by wire 57 to the wiper 58 which is adapted in its revolution to contact with the segments 50'and 52. These contacts are also tied together by wires 59 and 60 and to the printer by wire 61 so that at each operation Whether for a. dot ora dash the stop and start mechanism Will be opera-ted at the first movement and if it is a dot the impulse will be transmitted through the Wiper 48 and contact 49 or 51 as the case may be. depending upon the positions of the Wiper in starting, and thence by Wire to the printer. If the dash relay is operated the relay R Will first operate the starting mechanism and then become deenergized While the Wipers are moving from normal to contacting position and the relay R2 will close a circuit through battery ai, contact 40, Wire 57, Wiper 58 and segment 52 or 53 as the case may be, Wire 61 to the'printer and Wires 56 and 37 back to the battery m4 so that the printer will receive the dot or dash impulses neces-v sary to set up the printer in the usual Way.

The distributor in this case may be treated as typical only as various means of trans-v ductor or otherI conditions the received signals are of extremely low potential and of themselves are insuiiicicnt to operate con tactlng devlces, Where any considerable Work is to be performed it is desirable to magnify these signals and also to do this With mechanism which requires the minimum amount of labor to be performed by the received signal.

Up to the present time it seems to be conceded that a receiver of the movable coil of the DArsonval type has proved to be the most satisfactory, particularly for receivingr signals on submarine cables of high capacity. For magnifying signals-received on a movable coil of this type I have made use of what I believe to be an entirely new method of increasing the signals by employing an or regenerative coupling by 'meansof which f the .receiving coil has no' work to perform excepttomove in' response tothe signals andin connectionwiththiscoil Iy provide a separateinde en'de'nt` coil, preferably superim? posedfon-zt efotherfcoil but with no electrical connection thereyVith'"either` direct or inductive. In oth'erfvvords'it is non-inductively related to the 'coil Awhich kreceives the signals whileY moving in exact synchronism therewith. In this non-inductively related coil by `a movement coincident lWith the movement `of the receiving coil ythere is generated a current or current impulse having the same potential and polarity characteristics of the current which moves the receiving coil and these regenerated current impulses are used to change the potential of the grid element of a thermionic tube andtheincreased current from the plate circuit of the tube used to operate the recording or other receiving tube only for the respective positive and negative impulses. It Will be noted, however, that these tubes may be cascaded in the usual Way to ,magnify the regenerated impulses to any reqired or desirable potential.

Referring to Fig. 5 K represents a receiver of the usual galvanometer type with a movable DArsonval movable coil K" which will respond to current impulses of varying potential and polarity lin the usual way. Mechanically connected with this coil is a separate coil K2 noninductively related to the first coil and having no electrical connection therewith, so that When the coil moves in one direction in relation to the ermanent magnets of the receiver current impulses will be coil and when moved in the other direction current impulses will be generated and flovv in the opposite direction. The respective terminals of this regenerative coil K2 areyconnected by Wires .65 and 66 to the'grid elements of thermionicgtube's '67 and 68 and back to the center"ofrcoilKjthrough Wires .-73 and 76 sovthat in either ca 's'e the grids will be charged with positiver* potential.

The plate circuits 'of these respective tubes are connected 'by vv'vires 69 and .O'to relays upon which thel amplified ysignals aren to `be impressed. Various forms of relays could be used for this purpose, but I preferably employ `a device vofthe movable coil type having two separate andindependent coils on t-he same frame and adapted to move the contacting device of a relay or the stvlus ofv a recorder or other devicewhich may be used in connection therewith. These coils arc shown at Ka andvK.,.coil K3 being connected to the plate of the tube 67 by Wire 69 and las thence by wire 71 through the battery`72 and Wire 7 3 to the filament of tube 67, the ciduitfrom the plate of tube 68 is by Wire 70, coil -K4, w1re 74,' battery 75fand wire73 to the filament of the tube 68. The coils Ka and Ktwill be wound in opposite directions so that a current impulse-iin one coill Will.

move itin one direction and al similar impulse in the other vcoil \Wi1l move in the opposite direction, and as the-coils are mechanically connected so .as to moveftogetherthe contacting device .or stylus will move Vin different directions in response to these current impulses.

Now, when the coil K of thereceiver'4 posite direction a similar current will be generated in the-coil K2 and flow through. the other half ofthe coiland will change the potential on the grid of the tube 68- causing a corresponding impulse or current 'to pass through the coil K4 of the translating device and-thus 'operate the same but in the opposite direction.

By increasing thenumber of tubes inthe magnifier these regenerated current impulses can be magnified to any desired extent andv inasmuch as the regenerative coil K2 ismechanically connected but electrically disconnectedfrom the c oil K any disturbing in liuence on the coil K which might tend to distortthe signals will be eliminated inthe regenerative circuitV since the direction of movement of the coil and its speed of movement will bel the determining factors in the character of impulsesv generated in this coil.

While' this magnifying arrangement has been designed for Iuse in the alternating current system herein described it is obvious that it couldl be used with any system in- W-hichcurrent reversals are tob'e amplified. Having thusdescribed my invention, I

claim:

1 1. Ina telegraph system, means 'for producing alternating current reversals of an approximately sine Wave form from a direct current supply, and means for varymg' the amplitude of individual half cycles in phase with the alternating current frequency and employing impulses of different current values to producesignal elements.

2. In a telegraph system, the method of transmitting signal elements Which consists in producing alternating current reversais from'a direct current supply modifying the current half cycles in steps approximating av sine wave form, amplifying indivldual half cycles in hase with .the alternatmg current reversa s and gnploying the impulses Aof differentcurrent values for producin signal elements.. 3. n a telegraph systenna source of current supply, a polarity changing device having-,means for modifying each vhalf cycle of current impulses in steps so as to approxi- 1 mate a sine Wave form, and means for varying the amplitude ofthe individual half "gicycles in phase with the' alternating current frequency 1n response to transmitting de- ;fvices representmg dots and dashes.

4.- In a system for telegraphing, an automatic tape transmitter, andl a pole changing l device connected to said transmitter so' as to rotate 1n umson therewith, means for sending impulses from said transmitter into said polechanging device and variable resistance 1n sald pole changing device progressively arranged so that the potential of the impulses imparted thereto is increased inpsteps of t nieans for-varying the amplitude of" individual lapproximately a sine wave form, and

half cycles in phase with the alternating current reversals 1n response to current impulses from sa1d automatic transmitter.

5. A cable transmitting'device adapted to4 send current impulses of different polarity from a perforated tape, .a source of' current supply, and a pole changing device connected to the perforated tape transmitter to4 cause the same to move in step therewith,

resistance normally in circuit with the source of current to said pole changing device, and means for shunting a portionof said resistance in response to the current impulses from one set of perforations and for shunting additional resistance from said circuit in. response to another set of perforations.

6. In a telegraph systennmeans for imparting to a conductor alternatingcurrent of approximately sine wave form and for varying the amplitude of individual half cycles in response to current impulses, a revolving drum with two or more electrical insulated vsegments arranged on opposite .sides of a zero position, a'contact member operated by the current impulses to cause l the same to engage with the different segments in response tothe current impulses of different potential, and'mechanism operating in response to the contact with the'different segments to record the signal elements in the' form of dots and dashes.

7. In a transmitter, a4 rotating pole changing device, and a source of current supply, resistance in ,the circuit between the source of supply and -the' pole changing device,

transmitting relays adapted to shunt a part of the resistance from said circuit' when one relay is operated' and for shuntinflr additional resistance from said circuit W en the anotherv relay is operated, ksaid pole changing.

device havin means for varying thepotential of each impulse in steps whereby current impulses are 'transmitted to the conductor in approximately sine Wave form and the amplitude of half cycles varied'by the operation of the transmitting relays. in phase with the frequency ot the alternating current produced by said pole changing device. 8. In a. transmitter, a source of current supply, and av pole changing device having means for changing the resistance of the circuit in progressive steps so as to produce alternating current oi approximately lsine wave form, means for supplying impulses of different current values by the o eration ol transmitting relays representing c ifferent signal elements and means for locking said relays intheir o erated position during the movement of said pole changing device representing a half cycle and releasing'said ref lays when the half cycle is completed. y

9' In a telegraph S.VStemfthe method'foit i receiving. telegraph yimpulses of a plurality luyv the signa-l impulses a generator toprouce current impulses corresponding in pos larity and potential to the received signal impulses employingl the generated current' impulses for changing vthe potential on a thermionic tube and utilizing the change in potential for operating signal translating devices.

10. In a telegraph system, a receiver embodying 'a movable coil having a tongue to move in response to current impulses of different values and engage contacting seg- .ments arranged in pairs, said segments bepin'g supported on a rotating drum so that l the segments of one pair will be engaged by the tongue when moved by current impulsesv I of'one value and the segments of the other palr engaged bv the tongue 1n response to current of a cllflverentvalue, opera-ting relays contacts, a rotating pole changing device, and a source of current supply connectedto said pole changing devicethrough resistance, i,

' and means for shunting part of the resistance by the relay operated from one pair ot drum segments and for shunting additionalresistance when the relay is operated `trom the other pair of drum contacts.

11. In a telegraph system, a movable coil receiving device having a movable Contact arranged adjacent to a rotating drum insulated contacting segments on saiddrum on opposite sides of an insulating center segment, means for causing said contacting `deconnected in of current values which consist in-operatingv connected to the respective pairsotl drum` vice to move to the different segments on either side vgli the center in response to impulses of dllerent current values, an electricalv connect1on from the respectlve segmentson oneside of the center to the corresponding segment on the other side of the center, and relays connected to the respective pairs" of segments operated in response to contact with either one of a pair of segments and a recording device arranged to operate in response-to the respective rela s inv long and short marking of substantial y vertical form in response to the respective relays.

l2. In a telegraph system in connection with a receiving device comprising a movable coil'With a contacting arm, a rotating drum with multiple segments electrically l airs on opposite sides of a central insulating segment, transmitting relays connected to' the respective pairs of segments and adapted to be operated by varying movements of the movable coil in response to current 'impulses lof dli'erent current Values, a source of current supply, a

'pole changingdevice with means for producing alternatlng current of substantially "1 slne Wave form, means lfor varying the amplitudeof individual cycles by the operation of the transmittingrelays, and a stop and start mechanism for saidpole changing device operated by the contact of the movable arm With either one of one pair of drum segments whereby the pole changing device is started by and with the incoming signals. i

v13. Inan alternating lcurrent telegraph system in which individual half cycles are varied in response to dot and dash transmitting devices, a receiver of the movable coil type with a contacting device arranged adjacent to a revolving drum having segments on opposite sides of an insulating center, the segments on opposite sides being connected inpairs, transmitting relays connected to the respective pairs of segments and operated by the contact of said movable arm with either one of the respective pairs of the rotating segments, a rotating transmitting device operating in connection with said transmitting relays and a stop and start mechanism in connection With said rotating device, and means for operating the same by the contact of said movable arm with either one of one pair of the rotating segments so asto start the rotating transmitting device with the incoming signals.

14. In an alternating current cable system in which current impulses of different amplitude are supplied in phase. with the half cycles of the alternating current, a receiving device embodying a revolving drum and a movable contact, said drum having segments arranged in pairs, one segment for each pair being on the opposite side of the center of said drum, the movable contact being adapted to move in response current impulses of different current value, and a transmitting device operating in Iconnection with said receiving mechanism to repeat the impulses received upon said rotating drum and means for starting said transmitting' device when saidmovable contact engages either segment of one pair of said segments.

v 16, In a telegi'aphreceiver, tWo mechanically connected and non-inductively related coils suspended in proximity to magnets, one of said coils being connected to a telegraph conductor and the other of said coils being connected to atranslating device, said coils being operated together by the current impulses from the conductor to the coil connected thereto, the movement ofL the other,`

coil being adapted to generate currents of like character to those impressed on the first coilv and means for magnifyingthe generated current in said second coil. 17. In a telegraph receiver, two suspended coils mechanically connected together in roximty to magnets, one of said coils .be-4

ingadapted to receive current impulses and to. move the othercoil therewith, said second coil being ynon-inductively related Y to the rstrcoil and adapted by its'movement in relation to said -magnets to generate current impulses of corresponding characteristics to those received in the first coil and'mecha-v nism connected to said second coil forl translating the impulses generated therein. i

18. In a telegraph receiver, two independ ent suspended coils in roximty to magn ets, said coils being mec ianically'connected and n'on-inductively related,'one of said coils being ada ted to move by current impulses 'supplied t ereto and to move the. other coil and cause similar im ulses to be 'fenerated by the movement o said secon proximity to said magnets, means for amplifying the current' generated in` said sec:

ondcoil and a signal translating device opv erated by said amplified impulses.

19. In an alternating current telegraph system, means for impressing alternating current of approximately sine Wave form on a telegraph conductor and augmenting cervdrum having multiple. segments adapted to be engaged by saidv movable contact as the same is moved in response to the impulses of different current value and recording devices operated by these variable movements.

20. In a telegraph system in whichv alternating currents of approximately sine Wave form is applied to the conductor and the am litude of half cycles varied in phase the frequency of the alternating current in response to telegraph signals,a're ceiving device operated by the current impulses to cause long or short movements of a contacting d'evice, a revolving vdrum-having multiple segments arranged in pairs to be engaged by said contacting device, one pair by short movements and theotlier by nected tov said segments and means connected With one pair of segments to cause the transmittin device to start and move in synchronism with the received signals.

`21. In an alternating current telegraph system, a repeating device comprising a normally inoperative transmitter with means -long movements, a transmitting device conl for starting and rotating the same, a receiving device/having multiple contacts closed in response to impulses of different current value, one of said contacts being adapted-to ioo close*- a circuit t0 start the transmitting device and causeit to rotate in synchronism with the\received impulses and repeat the l same.

In testimony whereof, I have hereunto set my hand this 23rd day of April, 1924.

- V WiLLiAM M. issues, JR. 

